Ed Miliband's decision to body-snatch the inclusive concept of "one-nation" politics, in a cheeky raid on a sacred text of Toryism, owed its inspiration to an urgent need to reach out beyond the Labour tribe – and to an accident of geography.

Some scholar in the Labour leader's office must have spotted that on 3 April 1872, Benjamin Disraeli, spellbinding wizard of high Victorianism and Tory romanticism (and also leader of the opposition, two years from an election he would win) made a famous one-nation speech in Manchester's Free Trade Hall. The hall long gone its site is now occupied by the Radisson hotel, a few yards from where Miliband spoke.

Disraeli's one-nation theme said instead of being divided, the nation should be united by common passions, mutual concern and support,. Downtown Abbey is a sentimental version of that one-nation Toryism.

Though he called Gladstone's team "a range of exhausted volcanoes" Disraeli didn't actually say "one nation" in Manchester, nor in his second speech at the Crystal Palace, in June. He didn't have to: it was his brand.

As a dandified young MP in the turbulent 1840s, short of cash and looking for attention, he had written three novels on what was known as the condition-of-England question: the world's industrial powerhouse was a land of poor and wealthy on a scale without precedent.

With the radical Chartists on the march, slumps frequent in the primitive banking conditions of the day and a battle being fought over free trade (Disraeli opposed it), he called his fellow citizens "inhabitants of a different planet", in a famous passage in Sybil (1845) describing the "two nations".

Miliband wisely refrained from reminding his modern audience that Disraeli's one-nation solution was Tory paternalism – concern for the poor in contrast to the sharp-elbowed individualism of those grasping Liberal manufacturers and free traders (and their paper, the Manchester Guardian).

Since he had what the historian AJP Taylor would call "a flighty mind," Dizzy didn't much do detail: style was his forte. But he had given the skilled working class ("angels in marble") the vote in 1867, and he would legislate for public health, housing and factory reforms – themes of his 1872 speeches – when he finally won a Commons majority, in 1874-80, when he was already 70.

The phrase has inspired liberal Tories ever since, notably under Stanley Baldwin in the 20s and 30s, when Baldwin recoiled from the hard-faced capitalism of slump and strike, and again in the 50s, when the likes of Iain Macleod and even Enoch Powell started the One Nation group of MPs after Labour had included the phrase in its 1945 postwar manifesto. Harold Macmillan, a patrician PM, was their hero, for a while; Ken Clarke is their heir. But Thatcherism – Manchester liberalism revived – put the tendency permanently on the back foot.

So claims that David Cameron is an emollient, one-nation Tory never caught on. In truth, by 1874 Disraeli himself had already shifted to wooing working class votes via Tory Imperialism, a more effective formula than drains, and one which remains potent to this day.